Photomechanical printing.



BEST AVAlLABLE COF" UNITED ASTATES PATENT OEEIOE.

JOHN wf IPPERs, OE NEw YORK. N'. Y., AssieNORTO ALBERT HENRY WALKER, TRUsTEE, OE NEw YORK, N. Y.

PHOTOMECHANICAL PRINTING.

inilatwmasses' or in unbroken lines on paper or on cloth or on any other suitable surface or material, and thereby to print any geometric or other; pattern, picture, or design 1 5 which 'can'bfe made with such ungraduated deposits. "-yThi'nature of my invention consists in making a sensitive gelatin plate on an elastic baseand in exposing that sensitive gelatin plate` to llight through a translucent sheet having thereon a positive or a negative speci- -men of the pattern or picture or design to be reproduced and in developing that exposed gelatin plate by bathing it in water, and

z 5 thereby swelling some parts of its surface into relief, while leaving other parts of its surface in depressionh and in drying that developed gelatin plate in air and in afterward using that plate in producing intaglio,'relief, or planographic printing-surfaces with which to make the desired ungraduated deposits-of "ink orrc'olor, andv thus to print the particular pattern, picture, ordesign to be reproduced. Figurel of the ,accompanying drawings 3 5 represents a translucent glass or Celluloid Y e sheet having thereon a design composed of aiiat' area of opaque surface in the form of a five-pointed star and of a flat opaque circle lsurlroirid`1n'g.the star and of a series of unbroken lin'e's larranged around the circle. Aresents' a developed gelatin Aplate kgrdund of which is in depression and eliefgpprtyions 4of which' correspond with .the ta `.thejcircle, and the lines which are cl Fgnfl/and which are white in Fig. 2.

A* ,fromfthe depressed surfaces of the gelnlplate ofxFig. 2 and which deposits cor- I d with; the translucent areas of the Fig. 4 is a fragment of an in- .ly long strip of paper or cloth which hasllitd ythe opaque design' of Fig. 1 repeati v,edly,printed thereon by means ol' deposits of 1 Specification of Letters Patent.

Application filed June 26, 1905. Serial No. 266,932.

shown in Fig. 1 of the drawings from a trans- Blisfa .view of a copper roller which has dion its periphery cert-am deposits ofvt'ieth of an inch thick and provide it by means Fatented Feb. 1906.

printing-ink or color from those surfaces of 5 5- the copper roller of Fig. -3 which are white in vrthat figure.

The yprogram illustrated by the drawings is performed as follows: I- produce the 'sheet 6o lucent glass or Celluloid sheet by making the opaque designthereon, while making or leaving the background of the sheet translucent. The design on the sheet of Fig. `1 may be made thereon photographically or by the pen 65 or pencil of an artist, and in the latter case the artist may draw the design upon the translucent sheet as an original composition or may copy it from some other object or may trace it from a corresponding design on 7o paper or cloth or other material, 'or the design may be applied to the translucent sheet in any one of several other ways,jso as to produce the primary'instrumentality employed in my invention, which primary instrumen- 75 tality is a translucent sheet having some opaque design or pattern applied thereto.` The developed gelatin plate of Fig. 2 is made by the following means, in describing which I specify quantities by troy weights: I dis- 8o solve one younce of hard German gelatin in six ounces of water in a vessel 'of its own. I also dissolve one hundred and twenty grains of bichromate of ammonia in siX ounces of water in a vessel of its own. Thereupon I add the 8 5 solution containing bichromate of ammonia i tothe gelatin solution,` and then I add four ounces of alcohol. thereto, and then I filter the compound solution two or three times. vThe resulting composition of matter is a sensitized 9o gelatin emulsion, the ingredients of. which I mix togetherland filter and keep in a dark room or in a room dimlylighted with red light. I make a stock solution by mixing twentyeight ounces of water and one hundred and 95 eighty grains of citric acid 'and Vlive hundred and twenty grains of nitrate 'of-potassium and seventy grains of chrome-alum and half an ounce of liquid ammonia in a'vessel of its own. I then take two ounces of that stock solution and mix it with twelve ounces ofglycc'rin and six ounces of water in a vessel of its own, and thus produce a glycerin solution. I nextv take a sheet of Celluloid aboutOne-f- I O5 of a sand-blast Or otherwise with a uniform viinel if-grained surfaceon each of its sides unless it lis already so grained. -I thoroughly IOO clean this Celluloid sheet with alcohol, and then I glue it down upon a perfectly-flat bright steel plate abouta quarter of an inch thick by the following means: I take ordinary fish-glue and apply it to the upper surface of the steel plate by means of an inkingroller, and then I apply soft paper to that surface of the steel plate and press it down with a plain roller and leave it a few minutes to dry. Thereupon I apply more fish-glue to the upper surface of the paper, and then I press the Celluloid sheet down upon that paper by means of a plain roller, taking Care to exclude all air from between the celluloid and,

the steel. To confirm the union of the celluloid sheet with the steel plate through the intervention of the paper and the fish-glue, I pile the plate thus composed with other like plates, with sheets of felt interposed between them, and then I put a heavy Weight upon the top of the pile and leave it'there until each celluloid sheet is firmly and smoothly adherent to "s steel plate,` or I accomplish the same result by pressing the pile together in a powerful press. I next clean the celluloid side of the composite plate with alcohol, and I then pour my gelatin emulsion over ,that side of the plate, and `then I place that plate with that gelatin emulsion thereon exactly horizontal in a drying-oven, and I leave it there until the gelatin emulsion iscoherently dried and baked upon the celluloid surface. Thereupon I take the plate out of the oven and pour a second coat of the same gelatin emulsion on the first coat, and then I bake the plate, as before. This production of a sensitive baked gelatin plate must be made in a dark room or in a room dimly lighted with red light, which light may come from an incandescent electric lamp having a red bulb or may beadmitted to a dark room through a pane of red glass. The sensitive baked gelatin plate when finished must be kept dark and dry until it is used. I treat my sensitive baked gelatin plate as follows, so as to produce therefrom the developed gelatin late of Fig. 2: I put that sensitive baked ge atin plate in a photographic contact-frame With the sheet of Fig. 1 between it and the transthe sheet of Fig. 1 for spaces of time varying. The result of this of the sheet of Fig. 1.

lucent front of the frame and with its face upon the gelatin plate. I then expose the baked gelatin plate to light passing through lplate.

the translucent BEST AVAILABLE coP areas of the plate of Fig. 2 are uniformly h ardened by the exposure. The sensitive baked gelatin plate having been thus exposed to light is removed from the frame in a dark room and is immersed and bathed in that room first in slightly warm water and then in cool water. That bathing causes the absorption of water by the unhardened parts of the gelatin coating, and the absorbed water causes those parts of thegelatin coating to swell upward, and that swelling brings the design on Fig. 1 into relief on the gelatin surface of Fig. 2, while leavin in depression the other parts of the surface o the gelatin plate. If I am working in a temperature above 65 Fahrenheit, I next bathe the gelatin plate for from three to five minutes in a solution ofl five drams of chrome-alum in twenty-four ounces of water; but this bathing is not necessary when I am Working in a temperature as low as 60 Fahrenheit. the gelatin plate in the lsolution of chromealum tends to prevent the swollen area of the gelatin from receding entirely down to the original horizontal level of the plate when the water is expelled from that swollen area by the drying of the plate by means of a current of air produced by an electric fan or other- Wise and which drying is the next operation to which the plateis subjected. Still that drying causes the swollen area of the gelatin plate to somewhat recede; but the gelatin coating under that area remains comparatively soft and porous, while the elatin coating under the depressed surface 0I the plate continues to be comparatively hard anddense. I now strip the celluloid base of the developed gelatin plate of Fig. Z, Itogether with its gel- The bathing of IOO atin coating, away from the steel plate to which the celluloid base was glued before the gelatin emulsion was applied thereto, for the steel plate has now performed its function of keeping the celluloid sheet perfectly flat and perfect y level while the gelatin emulsion was being baked thereon.- 'l "-fl' I prepare the copper roller of Fig. 3 in the A following manner: I iirst apply, the abovedescribed glycerin solution to the flexible developed gelatin plate of Fi 2." Thatslution adheres to and is absor ed by the relief parts of that plate, because they are porous, but is repelled byits 4deprg 4edpaits,;fl) e 'lith'y are hard.- th` if I n l l gycerkin' from thgitflexi' Adeb A pate ymeanso `tissu" en lied A.e to'` and removed therefrpanfgliepegillltliis operation, if necessary, until no free' glycerin solution remains upo'n'uI the surface of the I next apply printing-ink to the flexile developed gelatin plate of Fig. 2 by a soft and elastic inking-roller or by'a succession of' such rollers, which ink is taken by the depressed surfaces of that plate; butmit is not vtaken by its relief surfaces, because it is rep'elled therefrom by the glycerin solution the plateis composed by melting together one pound of asphaltum, one pound of rosin,

half a pound of beeswax, one pound of mastic, and three ounces of mutton-tallow and then mixing v that composition with 'double its quantity ofthe crayon -ink of commerce, which crayon-ink is made of cooked linseedoil and lampblack without any fat. Thereupon Iy roll a plain-copper roller having a wellpolished periphery over the inked plate of Fig. 2 with pressure enough to causel sufiicient inkl to be transferred fromthe inked surface of the plate to the corresponding part of the periphery of the roller. Thereupon I change that ink into an enamel by means of the application thereto of an enameling-powder and by means of heat. That enamelingpowder is composed of two parts of rosin, one part of shellac, and two parts of alcohol, melted together and then cooled and finely pulverized. I apply that powder with a cotton ball to the inked surface of the copper roller,

' so as to make the powder adhere to the inked portions lof that surface without adhering to the naked portions thereof.. Then I heat the copper to a temperature high enough 7 to melt the enamelin -powder into the in to which itV has a hered. This heating'l results in changing the ink onthe surface of the copper roller into an enamel, and that enamel will protect those areas of the copper roller covered thereby from the eating of' the etching liquid, which is subsequentlyl applied to the copperk roller'. I next protect the interior -of the roller, if it is hollow, and also its ends,with asphalt varnish from the action of the etching-liquid, which I next apply to the periphery of-the roller. I make that application by simply causing the roller to rotate above a pan containing the etching liquid and. with all portions of the periphery of the roller successively passing vthrough the etching liquid in the pan as the roller is rotated. That etching liquid, which may be chlorid of iron, eats into the naked portions of the peripheryof the copper roller, while not affecting those portions of that periphery which are covered by the enamel. Icause the etching liquid to do its etching work for a greater or less, length of time, according as `I intend to etch more or less deeply into the periphery of the .copper roller, and thus give more or' less depression to its 'etched surfaces. After -the periphery of the copper roller has been etched I wash it with water to remove the etching s olution, and .then I remove the enamel from its relief surfaces with turpentine. The periphery of the copper roller having been thus provided-with depressed or intaglio printing surfaces the roller is used in a printing-machine as 1f lt had received those surfaces from the hands 0f .an enofraver. That use consists in a l une] Ilk or color to the' periphery 'of-the roller 812,495 BESTAVAILBLE coe and in scraping or wiping it away from the relief surfaces thereof and in drawing avstrip of paper or cloth between it and a plain roller taglio-printing, it is confined to printing fiatmasses or unbroken` lines as distinguished from graduated or modulated printing of pictures of natural or artificial subjects. Printing in flat masses of one color is illustrated by the star and by the circle in each copyy of the designshown in Fig. 4, while printing in unbroken llines'is illustrated by the parallel` Such printingis lines in the same design. applicable to silk or cotton dress goods and to oil-cloths and to wall-papers, where the designsto be printed are ungraduated, and such printing .is applicable to printing copies of line drawings or line engravings on velvet, or on satin, voi on other fabric, or on paper.

The processof this specification is not applicable to the production of any printingsurface capable of printing copies of pictures which are composed of graduated and structurelessgray. were to be taken as the original subject of this rocess, the result of the process would be a ailure to make any copy of that subject,

If such a graduated picture and that failure would be explainable as foli lows: The translucent negative photograph which would be made from the 'original graduated structureless gray= picture would also be in structureless gray, and that structure-c, less gray would be graduated from light to dark, and the different areas of that negative would transmit more or less light, according to their respective translucency. When the sensitive gelatin plate ofv this specification would be exposed to light through that negative and would afterward b e developed and dried, its surface would not be composed of uniform relief parts andniniform depressed parts, but would be" composed-of depressed parts of continually-varying depths, shading off into relief parts of continually-varying heights. Those depressed parts when provided Withprinting-ink would be filled with ink, though at varying depths, and that ink when transferred to a solid metal surface would cover all those areas of that surface which would be' opposite to thedepressed and ink-carrying parts of the develb )ed gelatin plate, l would thus be protected by thc ink thereon from the etching liquid afterward applied thereto and wouldtherefore be left in uniform relief thereby. "Then if the metal sur face were to be used'for"relief-printingit Those inked areas of At 1e metal IIO would print solid' ungraduated black yfor the graduated .structureless gray of the voriginal picture, or if the metal surface were to be used. for intaglio-'printing solid white would a pear on thegprinted paper or clothl where t eoriginal picture was graduated structureless gray. i v

Reliefrinting according'to my present invention differs from intaglio-printing in that the primary instrumenta ity of the process is y a negative translucent sheet instead of being a positive sheet, like that of Fig. 1, and in that' the copper roller is etched more deeply for relief-printingy than for intaglio-printing and in that the co per roller may be finely 4roughened for relie -printing instead -of being well polished for intaglio-printing before the ink is applied thereto from the gelatin plate.

A copper roller is said in the description to be the v.printing instrumentality which k.is ma'de'and used in my process; but such' a vroller may be made of aluminium, zinc, or

other metal and may be prepared and usedas set forth in this specification, eXce t that different metals are best `etched Wit different etching liquids, and While this specification articular'ly contemplates a metal roller as eingxthe best printing instrumentality to be pre ared'and used inthe process the process 1s a so applicable to the reparation and use of 'a plate of copper or ot er metal for intaglio-printing or for relief-printing in flat masses or unbroken lines.

Planographic printing Yon slabs`of stone or plates ,o zinc canalso be conducted according to my present invention by means which v include the process of my present claims and scription tobe temporarily glued down upon a flat and horizontal. steelplate while the gelvand position of the celluloid base causes the .the"flexible celluloid sheetis glued down atin coat is being'coherently dried and baked thereon. This flat and horizontal condition elatin coat to set and dry upon the celluloid hase with uniform thickness throughout all parts of its area. The flat plate upon which While the gelatin coat is setting and drying thereon may be of some other metal than steel, or it may be glass. The flexible celluloid sheet, with its gelatin coat, may be stripped from that flat plate before itis exposed to light or after it is exposed to liffht and before it is bathed in water instead of eing keV t upon the flat plate until after itis bathe in Water. If the flatjplatc is metal,

'. felt or soft rubber.

`Fig. 2 may be a flat andrigi V of bein a iexible celluloid sheet, provided BEST AvAiLAeLE 'coPx vthe)gelatindpifaa, with tile eaabie Celluloid be strip ed from the flat plate base, shoul before the glycerin so ution is applied to the gelatin coat in order to avoid any chemical reaction between the metalof the flat plate and any offtliechemicals in the glycerin solution; but ifthe"`-llat` late is glass the gelatin plate, with its iiexib e celluloid base, may be left on tlieiiat plate until after the glycerin solution isi-applied to the gelatin plate and, indeed, until after the. gelatin plate is inked.

Before ink is transferred from the inked gelatin plate to a solid surface the inked gelatin plate should be stripped from any flat plate to which it. may have been glued, be-

cause the gelatin plate lmust'beelastic at that time. That elasticity is necessitated by the fact that ,the inked gelatin plate must be pressed lvery hard against the copper roller or other solid surface in order-to transfer ink enoughfrom the depressions in the Vgelatin plate to the solid surface-and by the fact that relief parts of the surface of the gelatin plate if the base of that plate were rigid at that time and by the fact that good ink- 'impressions cannot be 'made between two unyielding surfaces. The -elasticity of that base at that fthat hard pressure would crush or distort'the time is made available' to prevent such crushing or -distortion and to produce good ink'irnpression by means ofthe presence below that base of some cushioning material, such as The permanent base of the gelatin plate o;

plate instea such a at and ri id plate is furnished on itsl upper surfaceavit an elastic layer of rubber or other elastic material, on the upper size yof which layer the gelatin emulsion is spread and upon which it is dried or baked. The

IOO

rigid foundation of such a gelatin plate may 'i be Glass and maybe a quarter of an inch thic or more. A layerl of elastic material, such as soft vulcanized rubber, may be spread over with'a rubber solution and then fastened down upon such a rigid foundation 'by drying that adhesive substance. Thereupon the elastic side of the plate thus composed may be coated with a solution of Waterglass and albumen, and that solution may be dried on that surface, so as to ive to the elastic side ofthe plate an .insolu le and porous surface for the reception of the gelatin emulsion and the firm retention of the gelatin film.

The elatin plate of Fig. 2 may be made with on y one coat of gelatin emulsion instead of two coats. In that case I make the gelatin emulsion with one ounce more of alcohol and two ounces less of water than I specify whenl two coats of gelatin emulsionare to be applied to the base of my. gelatin plate.

When a rigid late is' used'` instead of a flexible celluloid s eet as thefoundation ofa gelatin plate, that gelatin plate vwill retain mw BEsTAvAiLABLEcoP that foundation through all the stages of its z ln'lanufactnre and use, including the transferrenceof ink from its develo ed gelatin surface to the copper roller or ot er solid surface, which is applied to it for the reception of that ink. When that application occurs7 the elastic layer between the gelatin surfaceand the rigid foundation of the plate will yield enough to enable the copper roller or other solid suri face to talieink from. all the depressions in t that gelat-insurfaee Without crushing/ or distorting the reliefportions thereof.

Some ofthe instrumentalities and some of the transactions Which are described in this 4specification are also described in the Ipper's patent', No. 785,735, of March.28,'1905; but this specification differs substantially froml A. that patent in a'nuniber of essential particu- .'z'c` '.E-ach ofthe claims of thatlpatent contains elements and features which are absent from lars, and in its combination of elements, and

inits mode of operation, and in its result.

this specification, and .therV claim which I make in this s eciiication contains elements andfeatures-W ich are absent from that patent.

I claim as my invention;

The following process in photomechanical printing: making a gelal "in emulsion, sensitized with bichroniate of ammonia: applying that gelatin emulsion to a fatbase, and drying and baking it thereon: eX osing the resulting .baked gelatin platevt ight, through a sheet having a uniforinly-translucent area, and a uniformly-opaque area: developing that exposed gelatin plate,' by bathing it 1in Water, and thereby swelling into smooth and uniform relief, .that area thereof which Was under the opaque area of that sheet during the exposure, While leaving in smooth and uniform depression, that area thereof WhichA AWas under the translucent area of that sheet solid surface o stone or metal; all substany tially as described.

` v JOHN W. IPPERS. Witnesses: l

ALBERT H. WALKER, p HENRY L. RECKARD 

